How do you maintain and preserve water in the desert? Cooperation. This was the most important strategy used by the seven municipalities in southwestern San Bernardino County, Calif., when they joined the Inland Empire Utility Agency (IEUA) after it was founded in 1950. They banded together because water resources are so limited in southern California that its residents had to create IEUA as an independently elected district, which could import water from the state’s northern regions and collaborate on solving wastewater treatment issues. … The utility’s staff provided a tour of their Chino headquarters and Regional Plant 5 (RP-5) upgrade presently under construction during Automation Fair 2024 in Anaheim. RP-5 presently serves 200,000 residents and will take over RP-2’s solids processing duties once RP-5’s upgrade is complete. … [F]or RP-5 to assume RP-2’s role, it’s expanding its existing plant from 16.3 mgd to 22.5 mgd and building a new biosolids facility. Construction on the $330 million project began in 2021 and is expected to last another year and a half.